Spinal Arachnoiditis Ossificans: Report of Quadruple-Triggered Case.

Abstract

Arachnoiditis ossificans (AO) is a rare condition often associated with previous spine surgery. Here we describe a unique case of a patient affected by ankylosing spondylitis (AS), presenting with progressive neurologic deterioration due to AO. We also review the literature on evaluation and management of patients suffering from AO. The 65-year-old patient had a history of previous spinal trauma and related thoracolumbar surgery. Magnetic resonance imaging revealed multiloculated intradural/extramedullary cysts on the posterior surface of the spinal cord at Th9-L1, with clustered nerve roots. Computed tomography, with 3-dimensional reconstruction, demonstrated a likely ossification of both the dura and arachnoid from Th9 to S1. Microsurgical debridement of scar tissue from previous surgery, drilling of posterior ossified plaques at Th11-Th12-L1, and marsupialization and drainage of arachnoid cysts at Th11-Th12 were performed. We submit that AS, spinal trauma, epidural hematoma, and related surgery may be synergistic and independent factors in the etiopathogenesis of AO. This should be considered in patients with AS and/or a history of spinal surgery who present neurologic worsening.